In the post-genome era, one of the current challenges is to understand how epigenetic mechanisms impact cellular programming, development and disease. Histones, the proteins around which DMA is wrapped, carry covalent modifications that lead to gene activation or repression. Effector proteins read and translate this "histone code" through histone binding motifs. Recent studies have generated a wealth of information on patterns of histone modifications. Current technologies to assess histone modifications rely upon chromatin immunoprecipitation (ChIP). While powerful, ChIP has limited ability to probe the dynamics of epigenetic modification in living cells. I propose to use a modular histone tail binding motif from the polycomb (Pc) group of effector proteins to measure changes in histone methylation at a single locus in living cells. Synthetic biology is a new experimental paradigm that offers creative opportunities to investigate the mechanisms of epigenetic inheritance. The design of artificial biological systems is a means for testing our understanding of natural protein "modules." To this end, I will identify a peptide from PC that acts as a module that specifically recognizes methylated histone tails in mammalian cells. I will integrate this new modular part into a reporter system designed to track changes in histone methylation in dividing cells. Peptides that read specific histone modifications could serve as a new class of modular parts that interface bioengineered gene circuits with epigenetic signals that mark key steps in cell development. Heritable changes in the proteins bound to DMA (epigenetics) underlie mechanisms of cell development and disease. Research of the enzymes that mediate epigenetic changes has lead to the discovery of new cancer drug targets. Here, we use a bioengineering approach to probe the epigenetic phenomena. PHS 416-1 (Rev.10/05) Page 2 Number pages consecutively at the bottom throughout Form Page 2 the application. Do not use suffixes such as 2a, 2b. NAME OFAPPLICANT (Last, first, middle initial) Kirschstein-NRSA Individual Fellowship Application Haynes, Karmella A. (To becompletedbyapplicant - follow PHS 416-1 instructions)